None.
Not Applicable.
This invention relates to ball joints between two members, particularly of the type used in vehicle steering or suspension arrangements, and more particularly relates to cover means for preventing the ingress of contaminants to co-operating surfaces thereof.
Ball joints between members wherein forces are transmitted between the members whilst permitting relative articulation are to be found in steering systems of vehicles, and in general terms consist of three parts; (1) a ball member having an end portion that has a spherical curvature facing along the member from the end portion; (2) a housing member, comprising a container for at least part of the end portion of the ball member, having an aperture surrounding a longitudinal axis thereof to permit passage of the uncontained part of the ball member and provide a seat for the spherically curved surface; and (3) cover means, in the form of a generally tubular elastomeric (typically rubber) gaiter or boot which is attached at its ends surrounding to the housing member and the ball member so as to enclose that part of the spherical surface of the ball member end that is instantaneously, outside of the housing member, the flexibility of the gaiter permitting pivoting of the member with respect to the housing axis such that the spherical surface moves by way of the seat between the housing and the region enclosed within the gaiter.
Whereas the gaiter satisfactorily inhibits collection of contaminants on the spherically curved surface and ingress to the housing by way of the seat as the surface pivots, the presence of such a gaiter imposes constraints upon the functionality of the joint.
For instance, the angle through which the ball member can pivot is constrained by the stretching and puckering of the gaiter and siting of such a ball joint arrangement is constrained by a tendency for the gaiter material to perish prematurely when continuously operated exposed to heat radiated by a vehicle part such as an exhaust system or brake disc.
It is known to reinforce such an elastomeric gaiter with a steel reinforcement, primarily against physical damage. Such reinforcement may serve to conduct heat from within the gaiter material, but insofar as such heat is initially absorbed by the gaiter material, gaiter reinforcement provides no solution to premature perishing and may act to impede pivoting of the ball member.
The effects of radiated heat upon a ball joint arrangement of a vehicle steering system has been addressed in U.S. Pat. No. 6,095,712 which proposes interposing a heat shield between the heat source and the ball joint gaiter. Insofar as the shield comprises an additional component to manufacture and install, its shape is dependant upon the detailed design of the steering system and its disposition with respect to any heat source, militating against interchangeability between arrangements; that is, it is not multi-use component. Furthermore such a shield does not address any shortcomings in the range of ball member movements permitted by the elastomeric gaiter.
It is an object of the present invention to provide for a ball joint arrangement with a ball member having a spherical surface that moves within and without a housing member containing a seat, cover means for the prevention of contaminant ingress to the seat that is of simple construction and permits greater range of movement within the ball joint arrangement and greater protection from nearby heat sources than hitherto. It is also an object of the present invention to provide a ball joint arrangement including such a cover.
Briefly stated, according to a first aspect of the present invention, for a ball joint arrangement comprising a ball member, having an end portion that has a spherical curvature facing along the member from the end portion, and a housing member, comprising a container for at least part of the end portion of the ball member and an aperture surrounding a longitudinal axis thereof to permit passage of the uncontained part of the ball member and provide a seat for the spherical surface thereof, a ball joint cover which is operable to prevent ingress of contaminants to the seat comprises a ball seal arranged to extend around the longitudinal axis of the housing member as a ball sealing ring, the carrier adapted to be attached to the housing member operable to support the ball sealing ring biased against the spherical surface of the ball member without the housing such that said surface can slide relative to the sealing ring, and define a cover region between the carrier and the housing member, and barrier operable to inhibit ingress of contaminants to the seat from the cover region.
According to a second aspect of the present invention, a ball joint arrangement comprises a ball member, having an end portion that has a spherical curvature facing along the member from the end portion, a housing member, comprising a container for at least part of the end portion of the ball member, having an aperture surrounding a longitudinal axis thereof to permit passage of the uncontained part of the ball member and provide a seat for the spherical surface thereof, and a ball joint cover as defined in the preceding paragraph.
The foregoing and other objects, features, and advantages of the invention as well as presently preferred embodiments thereof will become more apparent from the reading of the following description in connection with the accompanying drawings.